Various AC frequency conversion techniques are known in the art, as well as various single to multiphase conversion techniques. A cycloconverter is a known device for AC frequency conversion. In one type of cycloconverter, an H-switch connects a load to a pair of AC power lines L1 and L2. The H-switch has one ON state connecting L1 to the left end of the load and connecting L2 to the right end of the load. The H-switch has another ON state connecting L2 to the left end of the load and connecting L1 to the right end of the load. The H-switch is toggled or switched between its one and other ON states at a given periodic frequency which mixes with the input frequency of the AC signal in heterodyne manner to output a plurality of frequencies, analogously to sideband generation.
The present invention provides in combination a system having a plurality of coordinated but irregular sets of switching times and logic means for a plurality of H-switches for performing in coordination the functions of phase and frequency conversion.